U.S. patent application number 14/375901 was filed with the patent office on 2015-09-03 for housing for an electrical module of a battery pack for a motor vehicle, and associated battery pack.
The applicant listed for this patent is Compagnie Plastic Omnium, Valeo Systemes Thermiques. Invention is credited to Gerald Andre, Gilles Elliot, Vincent Feuillard, Philippe Gilotte, Frederic Ladrech.
Application Number | 20150249238 14/375901 |
Document ID | / |
Family ID | 47754803 |
Filed Date | 2015-09-03 |
United States Patent
Application |
20150249238 |
Kind Code |
A1 |
Andre; Gerald ; et
al. |
September 3, 2015 |
HOUSING FOR AN ELECTRICAL MODULE OF A BATTERY PACK FOR A MOTOR
VEHICLE, AND ASSOCIATED BATTERY PACK
Abstract
A housing of a battery pack for a motor vehicle. A module
comprising several electric cells is associated with a
heat-regulating plate. A wall of the housing comprises an element
in relief and exerts a tightening force on the plate. The invention
also relates to the battery pack.
Inventors: |
Andre; Gerald; (Amberieu En
Bugey, FR) ; Gilotte; Philippe; (Benonces, FR)
; Elliot; Gilles; (Courcouronnes, FR) ; Feuillard;
Vincent; (Le Mesnil Saint Denis, FR) ; Ladrech;
Frederic; (Maurepas, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Compagnie Plastic Omnium
Valeo Systemes Thermiques |
Lyon
Le Mesnil Saint Denis |
|
FR
FR |
|
|
Family ID: |
47754803 |
Appl. No.: |
14/375901 |
Filed: |
February 1, 2013 |
PCT Filed: |
February 1, 2013 |
PCT NO: |
PCT/FR2013/050216 |
371 Date: |
July 31, 2014 |
Current U.S.
Class: |
429/99 |
Current CPC
Class: |
B60K 1/04 20130101; B60K
2001/0438 20130101; F28F 2013/006 20130101; H01M 10/617 20150401;
H01M 10/6551 20150401; F28F 2275/08 20130101; H01M 2/1077 20130101;
H01M 2/1094 20130101; H01M 10/613 20150401; Y02T 10/70 20130101;
H01M 2220/20 20130101; H01M 10/6556 20150401; H01M 10/647 20150401;
B60L 50/64 20190201; F28F 3/12 20130101; H01M 10/625 20150401; H01M
10/6554 20150401; Y02E 60/10 20130101; B60K 2001/005 20130101 |
International
Class: |
H01M 2/10 20060101
H01M002/10; B60L 11/18 20060101 B60L011/18 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 1, 2012 |
FR |
1250960 |
Claims
1. A housing of a battery pack for a motor vehicle comprising an
inner space designed to contain at least one module, comprising a
set of several electric cells associated with a heat-regulating
plate, the housing having at least one wall designed to rest
against the heat-regulating plate when the at least one module is
present in the housing, the housing comprising tightening means for
tightening a module against said at least one wall and in that said
at least one wall comprises, on its inner side facing towards the
heat-regulating plate, an element in relief contained within a
volume having a convexity turned towards the inner space of the
housing.
2. The housing according to claim 1, whose said at least one wall
is made from a thermoplastic material or a thermosetting plastic
material or a mixture of the two previous materials or molded
aluminum or cast aluminum.
3. The housing according to claim 1, wherein the tightening means
consist of means for closing the housing, comprising a bottom and a
lid, said bottom or said lid comprising said at least one wall
intended to rest against the heat-regulating plate.
4. The housing according to claim 1, wherein the tightening means
consist of means for attaching the module directly to said at least
one wall, for example using flanks tightened to two opposite sides
of the module.
5. The housing according to claim 1, wherein the tightening means
define a tightening direction (S) and the convexity of the element
in relief is defined by the following characteristics, the heights
being measured in the tightening direction: existence of at least
one highest point H (81) of the element in relief, existence of at
least one plane P of projection passing through the highest point H
(81) and parallel to the tightening direction (S), at least one
plane being such that in any area obtained by projection on the
element in relief of a disc of predetermined diameter located in a
second plane P' perpendicular to the tightening direction and
passing through the highest point of the element in relief, there
is at least one highest point H.sub.i whose orthogonal projection
h.sub.i on the plane of projection has a height on the plane of
projection which decreases with the distance between said
projection and the highest point H.
6. The housing according to claim 1, wherein the element in relief
comprises a solid having a convexity turned towards the inside of
the housing.
7. The housing according to claim 1, wherein the solid comprises a
network of ribs projecting from the inner side of the at least one
wall and lying within an envelope domed towards the inside of the
housing.
8. The housing according to claim 1, wherein the ribs of the
network of ribs are integrally molded with the at least one
wall.
9. The housing according to claim 1, wherein the solid is obtained
by giving the at least one wall a convex shape towards the inside
of the housing.
10. The housing according to claim 1, wherein the solid comprises a
set of studs formed on the bottom wall and each contact area is the
top of a stud.
11. The housing according to claim 1, wherein the element in relief
comprises a block of deformable material having an outer side of
convex shape towards the inside of the housing.
12. The housing according to claim 1, wherein the wall has a first
large dimension (L) along a first direction, a second large
dimension (I) along a second direction perpendicular to the first,
and wherein the maximum height of the convexity, i.e. the height
variation between the highest point and the lowest point of the
element in relief, is between 0.2% and 0.5% of one of these two
large dimensions of the wall, preferably of the smaller dimension,
and preferably between 0.1% and 2%, and preferably between 0.2% and
0.5%.
13. A battery pack for a motor vehicle, comprising a housing
containing at least one module, comprising a set of several
electric cells, associated with a heat-regulating plate, the
housing having at least one wall designed to rest against the
heat-regulating plate of the module, this at least one wall
comprising, on its inner side facing towards the heat-regulating
plate, an element in relief arranged and dimensioned to transmit to
the heat-regulating plate a tightening pressure exerted by the at
least one wall, this tightening pressure being such that the
element in relief and the heat-regulating plate remain in contact
with each other, notwithstanding a possible deformation of the at
least one wall caused by the tightening, this contact occurring at
least at points of the element in relief, distributed such that any
disc of 20 to 80 mm diameter, preferably 30 to 60 mm diameter,
drawn by projection on the heat-regulating plate contains at least
two of these points.
14. The battery pack according to claim 13, wherein each cell
comprises a rigid envelope and the envelopes of the cells in a
given module form a rigid block by being pressed against each other
along a transverse direction with their bottoms coplanar.
15. The battery pack according to claim 13, wherein the rigid
envelopes of the cells have a prismatic shape, with rectangular
bases.
16. The battery pack according to claim 13, wherein several modules
share the same heat-regulating plate.
17. Battery pack according to claim 13, wherein each module has its
own heat-regulating plate.
18. The battery pack according to claim 13, wherein the element in
relief comprises a pouch of an incompressible liquid or gel,
capable of transmitting uniformly and isotropically the pressure
placed on it and which results from the force tightening the at
least one wall against the plate.
19. The battery pack according to claim 13, wherein the liquid or
gel exhibits heat insulation properties.
20. The battery pack according to claim 13, wherein the liquid or
gel exhibits electrical insulation properties.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is the U.S. National Phase application of
PCT/FR2013/050216 filed Feb. 1, 2013, which claims priority to
French Application No. 1250960 filed Feb. 1, 2012, which
applications are incorporated herein by reference and made a part
hereof.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a housing for an electrical module
of a battery pack for a motor vehicle and associated battery
pack.
[0004] 2. Description of the Related Art
[0005] According to the invention, a "cell" designates a single
electrical device capable of producing electric current. A cell can
typically produce a voltage of between 2 and 4 volts, generally 3.7
volts, and is generally designed to be associated with other cells,
assembled in series, to supply a higher voltage.
[0006] A cell may have a rigid or flexible envelope. In the latter
case, we speak of a "pouch cell".
[0007] A "module" designates a set of several cells having a
self-supporting rigid structure, this self-supporting rigid
structure consisting either of a single rigid envelope containing
several cells with flexible or rigid envelope, or of the assembly
of several cells with rigid envelopes, placed beside each
other.
[0008] Lastly, a "battery pack" designates an electrical assembly
containing at least one module and the heat-regulating means for
this module, consisting of at least one heat-regulating plate.
[0009] The heat-regulating plate is generally cooled, and therefore
cooling for the module. It may nevertheless be used, at least
temporarily, to heat a module in order to bring it to optimum
operating temperature when the climatic conditions are unfavorable.
The heat-regulating plate may comprise internal channels
circulating a heat transfer fluid.
[0010] U.S. Patent Publication No. 2010/0025132A2 describes
electric cell modules, equipped with cooling means which may
consist of cooling plates maintained at a temperature of below
43.degree. C., heat sinks or systems circulating cold air from the
vehicle main cooling circuit.
[0011] In this type of assembly, the quality of the contacts
between the modules and the cooling plates must be excellent.
However, this result is difficult to achieve since it implies that
the dimensions of the cells and the cooling means must be highly
accurate, which is generally not the case. In addition, dimensional
variations of these constituents may appear or increase during the
life of the battery pack. Consequently, a simple stack, as proposed
in the state of the art, does not provide the conditions required
for optimum heat conduction between the modules and the cooling
means.
[0012] Faced with a problem of heat conduction between two
surfaces, it is also known to insert a heat-conducting interface
between these surfaces, such as a heat-conducting film, sometimes
called a "thermal pad". An example of such a thermal pad is a
silicone film having a ceramic load, which improves the heat
conduction between each cell and the cold plate by compensating for
small flatness or alignment defects of the lower wall of each cell
of the module and flatness defects of the cooling plate. However,
these compensations are approximately one tenth of a millimeter,
which is not sufficient to compensate for contact defects in all
cell assembly configurations. In addition, these compensations
using a heat-conducting film still depend on whether or not the
cooling plate is properly tightened against the cells.
[0013] There is therefore a need for an efficient solution to
tighten the cooling plate against the module whose temperature it
is supposed to regulate.
SUMMARY OF THE INVENTION
[0014] This invention aims to propose a novel, simple and
inexpensive solution, to guarantee excellent thermal contact
between a module and a heat-regulating plate. This solution may
advantageously be combined with that, already known, of adding a
heat-conducting film.
[0015] This invention relates to a housing of a battery pack for a
motor vehicle comprising an inner space designed to contain at
least one module, comprising a set of several electric cells,
associated with a heat-regulating plate, the housing having at
least one wall designed to rest against the heat-regulating plate
of a module when this module is present in the inner space of the
housing, this housing being characterized in that it comprises
means for tightening a module against the wall and in that the wall
comprises, on its side facing towards the heat-regulating plate, an
element in relief contained within a volume having a convexity
turned towards the inner space of the housing.
[0016] According to the invention, the wall designates the inner
side of a partition. This partition may be the bottom of the
housing, in which case the outer side of the partition is the outer
side of the bottom of the housing, or an inner partition of the
housing, separating for example two compartments thereof, in which
case the outer side of the partition is still located inside the
housing but not in the inner space containing the module.
[0017] Advantageously, the wall is made from a thermoplastic
material (e.g. polypropylene), a thermosetting plastic material
(e.g. polyester), a mixture of the two previous materials, this
material being optionally loaded with glass or carbon fibers,
polyethylene or any other load, molded aluminum (e.g. compression
molded), cast aluminum.
[0018] According to the invention, the fact that the element in
relief lies within a convex volume reflects the fact that it is
arranged and dimensioned to transmit to the heat-regulating plate a
tightening pressure exerted by the wall, this tightening pressure
being such that the element in relief and the wall remain against
each other, notwithstanding a possible deformation of the wall
caused by the tightening.
[0019] "Deformation caused by the tightening" designates any
variation in shape of the wall between the state in which it exerts
no pressure on the plate and the state in which it exerts the
tightening pressure on the plate. This expression therefore
excludes any geometrical defects intrinsic to the wall and obtained
independently of the tightening, for example due to a molding
defect. The deformation considered may be plastic or elastic.
[0020] The convexity of the element in relief is designed to
compensate for the deformations of the wall, generated by the
tightening and which are more pronounced in its center than near
its edges. Those skilled in the art will know, by calculations
and/or successive tests, how to determine the height and convexity
required to compensate exactly for the deformation of the wall,
considering in particular its dimensions, material, thickness and
the tightening forces.
[0021] The tightening means may comprise means for closing the
housing, comprising a bottom and a lid, the bottom or the lid
comprising the wall intended to rest against the heat-regulating
plate.
[0022] The tightening means may also comprise means for attaching
the module directly to the wall, for example using flanks tightened
to two opposite sides of the module, even if the housing has not
yet been closed.
[0023] In both cases, the tightening means define a tightening
direction S which may, for example, be perpendicular to the
wall.
[0024] In a special embodiment, wherein the tightening means define
a tightening direction, the convexity of the element in relief is
defined by the following characteristics, the heights being
measured in the tightening direction: [0025] existence of at least
one highest (absolute) point H of the element in relief, [0026]
existence of at least one plane P of projection passing through the
highest (absolute) point and parallel to the tightening direction
S, this plane being such that in any area (obtained by projection
on the element in relief of a disc of predetermined diameter
located in a second plane P' perpendicular to the tightening
direction S and passing through the highest point) of the element
in relief, there is at least one highest (relative) point H.sub.i
whose orthogonal projection h.sub.i on the plane of projection has
a height on the plane P of projection which decreases with the
distance between the projection and the highest (absolute) point
H.
[0027] In the above definition, "point" designates a very small
area of the element in relief similar to a mathematical point for
the requirements of the projection operation, this mathematical
point being substantially in the center of the area.
[0028] The highest points of the element in relief therefore form a
layer of contact areas with the heat-regulating plate which follows
a domed shape and ensures efficient tightening of the
heat-regulating plate, even if the wall deforms during tightening,
either immediately or over time.
[0029] The contact areas may form a continuous area or be
disjointed, being for example a set of "linear" (i.e. reduced to
areas of small width and long length), or "point" (i.e. reduced to
small areas) contact areas.
[0030] In a first embodiment of the invention, the element in
relief comprises a solid having a convexity turned towards the
inside of the housing.
[0031] According to a first variant, the solid comprises a network
of ribs projecting from the inner side of the wall and lying within
an envelope domed towards the inside of the housing, for example a
spherical cap, with a top substantially in the center of the
wall.
[0032] Advantageously, the ribs of the network of ribs are
integrally molded with the wall.
[0033] These ribs comprise a free upper edge opposite their
base.
[0034] This free upper edge may be convex, in which case the
contact between each rib and the heat-regulating plate occurs along
the free edge, which defines a linear contact area (i.e. a long
narrow area).
[0035] The free upper edge may also be undulating or castellated,
in which case the contact between each rib and the heat-regulating
plate occurs at the tops of this free edge, which define point
contact areas, formed by the tops.
[0036] According to a second variant of the embodiment, the solid
is obtained by giving the wall a convex shape towards the inside of
the housing, either due to the fact that the wall thickness is
relatively constant and concave to the outside of the housing, or
due to the fact that the wail is thicker, for example being thin
close to its edges and thickening towards the center, with its
outer side being substantially flat. Ribs may also be provided on
the outer side of the wall to strengthen it.
[0037] According to a third variant, the solid comprises a set of
studs formed on the bottom wall and each contact area is the top of
a stud.
[0038] To check the convexity of the element in relief in the
meaning defined previously, i.e.: [0039] existence of at least one
highest (absolute) point, [0040] existence of at least one plane of
projection passing through the highest point and parallel to the
tightening direction, [0041] a method may comprise: [0042] 1)
Defining a diameter D according to the dimensions of the plates and
the module. D will be between 20 and 80 mm, preferably between 30
and 60 mm. [0043] 2) Detecting the highest (absolute) point H of
the element in relief. [0044] 3) Creating, in the plane passing
through H and perpendicular to the tightening direction S, a grid
of square mesh of side D/ 2 (where 2 is the square root of 2) and
drawing discs on the convex surface of the solid. [0045] 4)
Detecting, inside each area projected (which is almost a disc,
ignoring the plate convexity), the highest point H.sub.i (relative
to this area) of the element in relief. [0046] 5) Taking a plane P
passing through H and parallel to the tightening direction and to a
first large dimension of the wall. [0047] 6) Projecting
orthogonally on the plane P the highest points H.sub.i obtained in
step 3 which are located at a distance from the plane P of less
than the diameter D, to obtain points h.sub.i. [0048] 7) Checking
that, on the plane P, the broken line passing through all the
points h.sub.i and through point H is convex. [0049] 8) Rotating
the plane P around the tightening direction at regular angular
intervals, until the entire area of the wall has been swept, and
repeating steps 5 to 6 at each interval.
[0050] In a second embodiment of the invention, compatible with the
previous, the element in relief comprises a block of deformable
material having an outer side of convex shape towards the inside of
the housing.
[0051] This deformable material may be a foam.
[0052] The block of deformable material may have the shapes
described previously, to produce contact areas forming a continuous
area or that are disjointed, being for example a set of linear or
point contact areas.
[0053] The previous embodiments may be combined. The scope of the
invention includes, for example, a housing having a thicker bottom
wall and completed by a solid having a convexity towards the inside
of the housing.
[0054] Advantageously, the wall has a first large dimension L along
a first direction, a second large dimension I along a second
direction perpendicular to the first. When the element in relief
has a convexity turned towards the inside, as in the case of a
network of ribs or a wall or a block of foam of convex shape, the
maximum height of the convexity, i.e. the height variation between
the highest point and the lowest point of the element in relief, is
preferably less than 2% of one of its two larger dimensions L and I
of the wall (i.e. excluding its thickness), preferably of the
smaller dimension. An interval of 0.1% to 2% is preferred. An
interval of 0.2% to 0.5% is even more preferred. For a square wall
of side 500 mm, the maximum height of the convexity of the element
in relief may be 2 mm. In absolute values, the maximum height of
the convexity should nevertheless preferably not exceed 5 mm,
irrespective of the dimensions L and I.
[0055] The invention also relates to a battery pack for a motor
vehicle, wherein it comprises a housing containing at least one
module associated with a heat-regulating plate, the housing having
at least one wall designed to rest against the heat-regulating
plate of the module, this wall having on its inner side turned
towards the heat-regulating plate an element in relief arranged and
dimensioned to transmit to the heat-regulating plate a tightening
pressure exerted by the wall, this tightening pressure being such
that the element in relief and the wall remain in contact with each
other, notwithstanding a possible deformation of the wall caused by
the tightening, this contact occurring at least at points of the
element in relief, distributed such that any disc of 20 to 80 mm
diameter, preferably 30 to 60 mm diameter, drawn (by projection) on
the heat-regulating plate contains at least two of these
points.
[0056] Ina special embodiment, each cell comprises a rigid envelope
and the envelopes of the cells in a given module form a rigid block
by being pressed against each other along a transverse direction
(with respect to the cell--plate--element in relief stacking
direction), with their bottoms coplanar.
[0057] Preferably, the rigid envelopes of the cells have a
prismatic shape, with rectangular bases. Other shapes are
nevertheless possible.
[0058] In a special embodiment, several modules share the same
heat-regulating plate. In another embodiment, each module has its
own heat-regulating plate.
[0059] According to the invention, good heat conduction is obtained
in the short term, conduction occurring between the module and the
heat-regulating plate as soon as the plate is tightened in the
housing, and/or in the long term, conduction between the module and
the heat-regulating plate being maintained over time to a greater
extent than if the heat-regulating plate had not been tightened in
the housing. In other words, the quality of the contact between the
heat-regulating plate and the module is such that the performance
of the heat exchanges between module and heat-regulating plate is
maintained during the lifetime of the vehicle without the effects
of ageing, especially temperature variations, vibrations, creep of
materials, being felt.
[0060] We can see the advantage of the element in relief according
to the invention to compensate for any tightening defect of the
plate against the module. Whether tightening is obtained by closing
the housing or by attaching the module to the wall using flanks,
there is a risk that the module dimensions are such that the
tightening points, i.e. the side walls of the housing or the points
of attachment of the flanks, are too far apart from each other,
allowing the plate to curve and no longer be tightly pressed
against the module in regions far away from the tightening points.
This is the case in particular if several cells are assembled
together to form a larger module.
[0061] With the element in relief according to the invention, the
heat-regulating plate is sandwiched between this element in relief
and the bottom wall of the module (with optional insertion of a
thermal pad), evenly over the entire bottom of the module.
[0062] An alternative to the presence of the element in relief
could comprise fastening the heat-regulating plate to the bottom of
each electric cell forming the module, but this measure would
require the presence of means for attaching the plate to the bottom
of each cell, as well as the supply and installation of attachment
members on the battery pack assembly line, generating a
non-negligible increase in material and energy costs. The invention
avoids these disadvantages.
[0063] Another advantage resulting from the fact that there is no
need to attach each cell to the plate is that a defective module
can easily be replaced, without having to dismantle the plate or
drain the circuit of heat transfer fluid circulating in the
plate.
[0064] In a special embodiment of the invention, the element in
relief comprises a pouch of incompressible liquid. As a variant,
this liquid is a gel.
[0065] The liquid offers the advantage of transmitting uniformly
and isotropically the pressure placed on it and which results from
the force tightening the wall against the plate. It therefore
advantageously replaces any other mechanical means designed to
uniformly distribute the housing tightening force over the
heat-regulating plate.
[0066] In addition, the liquid or gel may exhibit suitable heat
insulation properties, as well as electrical insulation
properties.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0067] The invention will be easier to understand on reading the
following description of embodiments given as non-limiting
examples, and referring to the attached schematic drawing in
which:
[0068] FIG. 1 is a perspective view from underneath of a battery
pack according to an embodiment of the invention, in its closed
housing and fitted under a vehicle;
[0069] FIG. 2 is a transverse cross-section with partial exploded
view of the battery pack shown on FIG. 1;
[0070] FIG. 3 is a perspective view of the battery pack whose
housing has been opened;
[0071] FIG. 4 is a view similar to FIG. 3, after removing one level
of electrical modules;
[0072] FIG. 5 is a perspective view from above of the open housing
with its content completely removed;
[0073] FIG. 6 is a perspective view from above of the open housing
containing a heat-regulating plate;
[0074] FIG. 7 is a diagrammatic view of assembled elements of one
level of the battery pack;
[0075] FIG. 8 is a diagrammatic view from underneath and at a
larger scale of part of the heat-regulating plate and its areas in
contact with the bottom wall of the housing;
[0076] FIG. 9 is a diagrammatic sectional view along IX-IX of a
part of the bottom wall corresponding to the part of the
heat-regulating plate shown on FIG. 8;
[0077] FIG. 10 is a perspective view of an alternative embodiment
of the bottom wall, whose element in relief comprises a network of
ribs; and
[0078] FIG. 11 is a general sectional view of a battery pack
comprising a pouch of gel as element in relief.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0079] FIG. 1 shows a battery pack 1, fastened under a floor 3 of a
motor vehicle, inside a compartment 5 provided for this
purpose.
[0080] The floor 3 may be made from polypropylene.
[0081] This arrangement of the battery pack 1 under a floor 3 is
only a non-limiting example.
[0082] The battery pack 1, more visible on the exploded view of
FIG. 2, comprises a substantially parallelepipedic housing 7 made
from mixed material formed by two upper 7a and lower 7b halves,
each having a junction edge 8a, 8b. The edge 8b of the lower half
7b has a seal 9, shown on FIGS. 4 and 6.
[0083] The large sides 11, respectively 13, of the upper half 7a,
respectively lower half 7b, comprise attachment lugs 15,
respectively 17, for fastening the housing 7 to the floor 3.
[0084] The exploded view of FIG. 2 in particular shows that the
elements present in the housing form two levels E1, E2 of assembled
elements, the two levels being substantially identical and each
comprising an inner space.
[0085] The invention is not limited to this embodiment and the
housing could contain only one level, or on the contrary more than
two levels.
[0086] Level E1 will now be described. Level E2 contains the same
elements, referenced using the same numbers and the sign '.
[0087] As can be seen more clearly on FIG. 3, in this case a level
contains 5 electrical modules 19-1, 19-2, 19-3, 19-4, 19-5
(designated generically by reference 19) placed beside each other.
Each module is itself composed of ten prismatic cells with
rectangular base 21-1-1, 21-1-2, 21-1-3, 21-1-4, 21-1-5, 21-1-6,
21-1-7, 21-1-8, 21-1-9, 21-1-10; 21-2-1 to 21-2-10; . . . ; 21-5-1
to 21-5-10 (designated generically by reference 21 in the remainder
of this document) tightened against each other by their large sides
and arranged with respect to each other such that their bottoms are
coplanar and such that their small sides are also coplanar, so as
to form a generally rectangular parallelepiped. Other cell shapes,
or a different configuration of the set of cells forming a module,
could of course be considered, possibly giving the module a
different overall shape, provided that the bottom of the set of
cells is flat or substantially flat.
[0088] In a module 19-1 (respectively 19-2, 19-3, 19-4, 19-5), the
cells are held together by flanks 23-1 (respectively 23-2, 23-3,
23-4, 23-5, the flanks being designated generically by reference
23) placed against the two small end sides of the parallelepiped
and connected together by four tie rods 25 (two on each large side
of the parallelepipedic module). The five modules are held
substantially in the same plane when they are placed side by side
to form one level of the housing.
[0089] As can be seen on FIG. 7, the flanks 23 extend above and
below the small end sides of the parallelepiped, leaving in
particular, under the bottoms of the cells 21, a space 31,
advantageously of height e between 10 and 20 mm, and more precisely
17 mm in this embodiment.
[0090] In the electrical modules 19 so assembled, the bottoms of
their cells 21 lie substantially in the same lower plane, forming
the ceiling of the space 31.
[0091] A heat-regulating plate 33, according to the rectangular
embodiment example, is placed under all the bottoms of the cells 21
of the level. In this case, it is therefore shared by the five
modules 19. In an alternative embodiment, each module 19-1 to 19-5
could have its own plate. The heat-regulating plate 33 is
dimensioned to fit in the space 31. It is made from aluminum and,
along its two large sides, has two main channels 35, extended by
tubes 37 carrying heat transfer fluid, each tube opening into a
hole in the housing 7 shown on FIG. 3. In level E2, the tubes 37'
cross the holes 39, 41 of the lower half 7b of the housing 7. Each
main channel 35 communicates with the other via secondary channels
(not shown) distributed in the thickness of the plate. Other plate
configurations are possible with, for example, main channels
arranged in positions other than along the large sides of the
plate.
[0092] As shown on FIG. 7, he main channels 35, contained in the
space 31 with the heat-regulating plate 33, extend out of this
space 31 by a height d.
[0093] On the heat-regulating plate 33, a heat-conducting film 43
(film 43 of level E2 is more clearly shown on FIG. 6), preferably
made from ceramic-loaded silicone is provided to improve the heat
conduction between the modules 19 and the plate 33. The thickness
of this film 43 may vary, in particular from 0.5 to 1 mm and adapts
to the reliefs caused by surface imperfections of the bottoms of
the cells 21 and of the plate 33, thereby increasing the contact
areas and therefore the heat conduction paths between these two
parts.
[0094] The flanks 23 have lower edges 45, respectively upper edges
47, used to attach them, for example with screws 49, to a
separation wall 53 which forms a bottom wall for the upper level
E1. The wall 53 is more clearly shown on FIG. 4. On the lower level
E2, the equivalent of the wall 53 is the bottom wall 53, which can
be seen more clearly on FIG. 5.
[0095] Within the meaning of the invention, the walls 53 and 53'
are intended to rest against the heat-regulating plate 33, 33' of a
module. The housing comprises two inner spaces (not referenced),
i.e. one for each level, each one being intended to contain a
module 19 composed of a set of several electric cells 21.
[0096] In the remainder of the description, the inner side of a
wall 53 or 53' will designate the side of this wall turned towards
the inner space containing the module 19 interacting with the
heat-regulating plate 33, 33' in contact with the wall.
[0097] The sectional diagram of FIG. 7 shows more clearly how the
stack of the wall 53, the heat-regulating plate 33 (equipped with
the film 43) and the cells 21 is created.
[0098] In particular, we see that the wall 53 comprises a network
of crossed and perpendicular ribs 55 on its inner side, at the
surface of he heat-regulating plate 33 contained between its main
channels 35.
[0099] Although difficult to see on the figures due to the
relatively small height variation between them, the ribs 55 are
arranged in a network of crossed ribs lying within an envelope
domed towards the inside of the housing and forming, within the
meaning of the invention, an element in relief having a convexity
towards the inside of the housing.
[0100] More precisely, L (FIG. 4) being the largest dimension of
the wall, in this case its length since the wall is rectangular,
and I being its second longest dimension, in this case its width,
the envelope containing the ribs 55 is domed only in a plane normal
to the wall and parallel to the direction of its width I. In other
words, in transverse section parallel to the direction of the
length L, the height of the ribs 55 is the same along the entire
length L, but this height varies depending on the cross-section
considered and is maximum on the central axis of symmetry X of the
wall.
[0101] In the example of this embodiment, the maximum height of the
convexity, that is, the height variation between the lowest point
and the highest point of the network of ribs 55 is 1.5% of the
width I (the smaller of the two largest dimensions L and I of the
wall 53).
[0102] On each of its two longitudinal sides, the network of ribs
55 has a recess 57 of depth d dimensioned to contain the main
channels 35 of the heat-regulating plate 33.
[0103] Along each recess 57, supports 59 parallel to the direction
of the width act as seats for the lower edges 45 of the flanks 23.
Some of these supports 59 include a tightening chimney 60 which is
aligned with a hole 44 in the lower edges 45 of the flanks 23. Each
edge 45 has two holes 44 and extends along a length corresponding
to six supports 59 (numbered in the remainder of the document from
first to sixth, in the direction of the length), covering entirely
only the second to the fifth supports 59, while it covers only half
of each of the first and sixth supports 59, each of these two
supports receiving, on its other half, the flank next to the flank
23 considered.
[0104] The tightening chimneys 60 determine the tightening
direction, which is therefore here, as will often be the case,
perpendicular to the general plane of the wall 53.
[0105] As can be seen more clearly on the zoom of FIG. 7,
tightening the screws 49 crossing the holes 44 in the lower edges
45 of the flanks 23 and the tightening chimneys 60 brings the
modules 19 and the wall 53 closer together, thereby sandwiching the
heat-regulating plate 33 between the wall 53 and the cells 21 as
well crushing the film 43 between the heat-regulating plate 33 and
the bottoms of the cells
[0106] Due to the convex shape of the envelope of the ribs 55,
deformation of the bottom wall 53 during tightening, potentially
increasing on moving towards the axis of symmetry X of this wall
53, is compensated by the increased height of the ribs on
approaching this axis.
[0107] In a given level, therefore, the following elements are
stacked: [0108] cells 21, 21' grouped in modules 19, 19', [0109] a
heat-regulating plate 33, 33', [0110] a wall 53, 53' tightened
against the modules by tightening means.
[0111] FIG. 8 shows the areas of the heat-regulating plate 33 on
which the pressure of the ribs 55 is exerted after tightening.
[0112] These areas are designated as "contact areas".
[0113] This pressure results from contact with the highest areas of
the bottom wall 53.
[0114] In practice, the contact areas can be indicated by
depositing a colored powder on the free upper edges of the ribs 55.
When the heat-regulating plate 33 is tightened by the bottom wall
53, this power is transferred onto the plate 33 to produce the
pattern shown on FIG. 8.
[0115] As can be seen on FIG. 8, if we consider any disc of
diameter D on the heat-regulating plate 33, there is always at
least one contact area. This contact area corresponds, on the
bottom wall 53, to the highest point Hi of the free upper edges of
the ribs 55.
[0116] Therefore, disc 61 contains the highest point 63, disc 65
contains the highest point 67, disc 69 contains the highest point
71, disc 73 contains the highest point 75, and disc 77 contains the
highest point 79.
[0117] In addition, the bottom wall 53 has the highest point
81.
[0118] Each of these highest points 63, 67, 71, 75, 79 and 81 is at
the top of a rib 55 in the network of ribs, as shown on the
cross-section of FIG. 9.
[0119] This figure also shows that the cross-section of the tops of
the ribs 55 may be rounded, which reduces the area of each contact
area. However, since the material of the ribs can deform
(elastically or plastically), the top of each rib can crush such
that the contact areas are not simple lines.
[0120] The heat-regulating plate 33 is therefore kept in optimum
contact with the cells 21 over its entire surface, it being
understood that "optimum" refers to the fact that the contact
between these two parts occurs at least in areas sufficiently close
together so that two adjacent points are not separated by more than
the distance D or, in other words, so that any circle of diameter D
drawn on the heat-regulating plate 33 contains at least two of
these contact areas, resulting in a relatively high and regular
density of contact points between the plate and the cells.
[0121] In the embodiment of FIG. 10, the wall 53 has two large
dimensions L and I. It comprises an element in relief composed of a
network of crossed perpendicular ribs 90 of square mesh.
[0122] This network of ribs 90 is convex, in the sense that the
tops of the ribs 90 lie within a envelope domed upwards (with
respect to the figure).
[0123] The convexity of the envelope extends in the two directions
of L and I, with a maximum height, i.e. a height variation between
the lowest point and the highest point, advantageously of 2% of I,
although, on the schematic diagram of FIG. 10, the curvature has
been accentuated to clearly illustrate the meaning of the
convexity.
[0124] The convexity of the network of ribs can be checked by
proceeding as follows.
[0125] 1) Define a diameter D according to the dimensions of the
heat-regulating plate, which in this case is assumed to have the
same width I and the same length L as the wall. In this case, we
take D=50 mm.
[0126] 2) Detect the highest point H of the wall, along the
tightening direction indicated by the arrow S pointing upwards,
[0127] 3) Draw a grid with square mesh of side D/ 2, having an
intersection at point H. At each intersection of the grid, draw a
circle of diameter D.
[0128] 4) In each disc of diameter D, find the highest point
H.sub.i.
[0129] 5) Take a plane P passing through the point H and parallel
to the direction S and to the direction of the length L.
[0130] 6) Project orthogonally on the plane P the highest points
H.sub.i obtained in step 3 which are located at a distance from the
plane P of less than the diameter D, to obtain points h.sub.i.
[0131] 7) Check that, on the plane P, the broken line passing
through all the points h.sub.i and through point H is convex.
[0132] 8) Rotate the plane P around the direction S and repeat
steps 5 and 6.
[0133] An alternative method consists in determining whether a
direction of "non-convexity" exists, along which all the points
obtained in step 3 present in a plane parallel to this direction
have the same height. If it exists, execute steps 5 to 6, choosing
a plane P parallel to S and perpendicular to the direction of
"non-convexity", sweeping the entire wall at the plane P by
translational motion over a distance D.
[0134] In the embodiment of FIG. 11, the ribs described previously
are replaced by a pouch of gel 99. The bottom wall 101 of the
housing is flat and has no ribs. The pouch of gel 99 forms an
element in relief of the bottom wall 101, which transmits the
pressure exerted by the bottom wall 101 to the heat-regulating
plate, homogeneously and at every point of its surface.
[0135] Once again, the pressure transmitted is the same at every
point of the heat-regulating plate 33, irrespective of the
deformation suffered by the bottom wall 101 when tightening the
screws 49 fastening the flanks 23 to the bottom wall 101.
[0136] Obviously, the examples described above are given as
illustrations only and cannot be construed as limiting the scope of
the claims.
[0137] While the system, apparatus, process and method herein
described constitute preferred embodiments of this invention, it is
to be understood that the invention is not limited to this precise
system, apparatus, process and method, and that changes may be made
therein without departing from the scope of the invention which is
defined in the appended claims.
* * * * *